Field of the Invention
This invention relates generally to aircraft and, more particularly, to an aircraft with a controlled flow of air over an airfoil, thereby permitting both vertical takeoffs and landings, as well as vertical and (normal) horizontal flight. The aircraft has passages for redirecting the air flowing over the airfoil to the front of the airfoil and to produce a force in a direction of the desired flight path.
Discussion of the Related Art
In recent years, the increase in the power and efficiency of engines along with the development of lightweight structural materials has provided increased interest and incentive for the practical development of low cost, lightweight personal aircraft. These aircraft have become more inexpensive and more readily available as the improved technology has been applied to the problem.
Notwithstanding the improvements in the newly developed aircraft, these vehicles have been subject to the traditional limitation that the aircraft must develop forward speed relative to air mass before the lifting properties of the airfoil can be utilized. To overcome this problem, aircraft, such as helicopters, have been developed in which the engine and a suitably-oriented propeller provide thrust from the engine literally to drag the aircraft into motion in a vertical direction. Similarly, vertical liftoff aircraft have utilized directed flow of the exhaust of jet engines to produce vertical motion.
However, in the cases of these types of vertical travel aircraft, the apparatus has been complex and expensive, and has attempted to solve the problem of vertical travel through the use of directed force rather than the attempt to utilize the properties of a lifting body. For example, U.S. Pat. No. 3,987,981, "Roll Control For Aircraft, Particularly Flying Barrels, Adapted to be Driven by Means of Ducted Fans," uses louvers or flaps to direct the flow of air from a ducted fan in the opposite direction from the direction of the directed flight pattern. A similar technique is shown for U.S. Pat. No. 2,610,005 "Propulsion Means for Vertical Rising Aircraft." In U.S. Pat. No. 3,901,463 "Lift and Propulsion Means for a Vertical Take-off and Landing Aerodyne" provides two propellers that can simultaneously force air into a partially enclosed chamber, and impart a force in direction opposite to an opening in the chamber. U.S. Pat. No. 2,623,712 "Airplane with Pivotally Mounted Sustaining Wing" provides a wing structure that can be pivoted on a fuselage to provide some measure of control over the flight path. U.S. Pat. No. 2,008,737 "Airplane", discloses a passage in the aircraft so that the force of air against the walls of the passage provide a lifting force for the aircraft. And U.S. Pat. No. 3,017,139, "Ring Airfoil Aircraft" uses flaps to direct the flow of air and provide a lifting force. In each of these examples, the directed air flow is the means of controlling a flight path.
A need has therefore been felt for a simple aircraft configuration that can conveniently and safely move in a vertical direction and that makes use of the properties of the lifting surfaces to provide the requisite vertical force.